1. Field of the Invention
The present invention relates to piping and piping systems, but more particularly the present invention relates to the detection of leaks in especially remote piping systems, with the indication of a leak being manifested by the closure of valves or like controller Even more particularly, the present invention relates to an apparatus for detecting leaks in suspect piping fittings as are a part of the "Christmas tree" portion of a natural gas well, and the closure of well control valves coincident with the occurence of such a leak from the suspect fitting.
2. General Background and Prior Art
In the production of natural gas, as well is normally drilled with a length of pipe known as a "drill string". The drill pipe is individually made up of sections which can be, for example, thirty (30') feet. The drill pipe is enclosed normally in a casing which is also welded or jointed. Casing is then cemented into place from the bottom up. At the head of the casing, the crew installs a master valve that may be closed quickly and surely to shut off the flow of gas. Above this valve is placed a "Christmas tree". A Christmas tree is merely an assembly of pipes and valves that allows the gas to flow into gathering lines. These gather the output of several wells and carry the fuel to the crosscounty pipelines for remote transmission of the gas. (See FIG. 1 of the specifications.) Many of the oil wells and gas wells presently in use are in remote areas, such as many miles offshore, in marshy areas, or in areas which are generally uninhabitable. A great problem arises when these remote or "robot" oil and gas rigs develop minute leaks which are not indicated and are not detected until a human inspection or until a disaster or accident occurs.
In offshore oil or gas wells, frequently the oil and/or gas partially consists of sand or other abrasive mineral which can eat away and mechanically erode the inner portions of a pipe or piping system. The problem is accentuated at fittings where the fluid stream must turn or otherwise be redirected, producing turbulence. The oil or gas stream containing sand, thus, can easily eat away and produce eventual cracks or leaks within fittings, such as, the choke jacket of the "Christmas tree" portion of a typical oil and gas well.
Engineers can generally determine what parts of the Christmas tree, or piping system are most turbulent and thus, where mechanical erosion will most probably occur. These "suspect" fittings once identified, need to be either regularly inspected, or replaced on a regular basis.
This is both time consuming and expensive, and additionally, it is impossible because of the economic considerations. For example, oil and gas wells which are many miles offshore may only be reached by boat or helicopter, and the cost of inspecting them on a daily basis can be prohibitive.
Thus, there is a need for a simple and inexpensive device which is easy to install on existing piping systems such as, the "Christmas tree" portion of an oil and gas well which system can readily determine the presence of even the most minute leak, and indicates the presence of such a leak by, for example, closing a gate valve or like control valve, halting the flow of fluids through the piping system for a leak allows precious minerals to escape, or causes an environmental disaster, or causes a disaster which can jeopardize human lives and property.
It is to this general field that the present invention is directed.